Hypodermic syringe



2 Sheets-Sheet l INVENTORS.

Albert Anfhony Poli, Jr. Ronald John Fayck THE /R ATTORNEYS A. A. POLI,JR., ETAL HYPODERMIC SYRINGE n f. l s: E- MEE 4Dec. 22, 1964 Filed Sept.25, 1962 2 Sheets-Sheet 2 INVENTolgs. Albert Anthony Po/J, Jr. RonaldJohn Fayck v 54AM THE/R ATTORNEYS Dec. 22, 1964 A. A. POLI, JR., ETALHYPODERMIC SYRINGE Filed sept. 25, 1962 United States Patent O 3,162,217HYPQDERMIC SYRINGE Albert Anthony Poli, Jr., Pittsburgh, and Ronald JohnFaycik, Johnstown, Pa., assignors to Fisher Scientilic Company,Pittsburgh, Pa.-

Filed Sept. 25, 1962, Ser. No. 226,636 3 Claims. (Cl. 141-27) Thisapplication relates to a hypodermic syringe, more particularly ahypodermic syringe used in conducting analyses by gas chromatography.

In carrying out analyses .by gas chromatography, a stream of inertcarrier gas is caused to liow through one or more chromatographiccolumns and through thermal conductivity cells positioned at the exitend of each column. A sample of the mixture to be analyzed is injectedinto the carrier stream in advance .of the irst column. As the samplepasses through the column or columns, the mixture is separated into itsseveral components, which components elute one at a time from a columnand are detected by a thermal conductivity cell which in turn sends asignal to a reading .or recording device. In order to obtain accurateand reproduceable results by this method of analysis, it is importantthat samples of uniform volume be injected into the carrier stream, andit is also important that the sample be injected into the carrier streamat a uniform rate.

Generally, samples analyzed by gas chromatography are relatively small,and are injected into a carrier stream by means of a hypodermc syringeinserted through a rubber serum cap. It requires considerable skill onthe part of an operator ,using a hypodermic syringe to repeatedly insertsamples at a uniform rate and of uniform volume. We have invented ahypodermic syringe whereby these results can readily be obtained withoutprior practice or training.

The hypodermic syringe which we have invented is generally similar ,toconventional syringes having a glass tube, a needle at one end of thetube, and a plunger which can 4be moved within the tube towards and awayfrom the needle to move liquids or gases in and out of the tube throughthe needle. `rIhe plunger is mounted on a plunger rod which carries ahand knob at Vits outer end so that the operator can move the plunger inthe glass tube.

In our syringe, we also provide a compression spring .which .engages therod and presses the plunger against the fend .of the needle within theglass tube. When the plunger is moved away from the end of the needle todraw liquid or gas into the tube, the spring is compressed and uponrelease ofthe plunger rod, the spring will move the plunger towards theneedle to eject liquid or gas from the tube.

We also provide means for releasably holding the plunger rod against theforce of the spring when the plunger is moved from the needle. Theholding means can be adjusted so that the amount of liquid or gasexpelled by the plunger upon release of the-rod can be adjusted. Theplunger can readily be brought back to the same holding positionrepeatedly so that upon release of the plunger samples of uniformquantity will be ejected at a uniform rate.

In the accompanying drawings, we have illustrated certain presentlypreferred embodiments of our invention in which:

FIGURE 1 is a longitudinal section of one form of our syringe showingthe plunger withdrawn;

FIGURE 2 is a partial side view of a part of the syringe shown in FIGURE1;

FIGURE 3 is a section along the lines III-III of FIG- URE 1;

,FIGURE 4 is a side view partially in longitudinal secl. tion of thesyringe in which the plunger is shown in positionafter a sample has beenejected;

3 i $2 ,Z i7A Patented Dec. 22, 1964 FIGURE 5 is a longitudinal sectionof a modified `form of our syringe, showing the plunger withdrawn;

FIGURE 6 is a side elevation partially in section of the syringe shownin FIGURE 5 with the plunger in position after a sample has beenejected; and

FIGURE 7 is a section along the lines VII-#VIII of FIGURE 5.

Referring to the drawings, our syringe comprises a `hollow hypodermicneedle 8 mounted in one end of a glass tube 9. A metal sleeve 1lisurrounds the glass tube and is partially closed at the needle end ofthe tube 9 leaving an opening II through which a plug 12 having a flange13 is inserted. A similar iianged plug I4 is inserted in the end of theglass tube. The anged ends of the two plugs 12 and I4 face each other,and each has a central sernicircu-lar cavity l5 which together form aspherical cavity to receive a small metal ball I6 mounted on the needle8. The plugs 12 and 14 are drilled longitudinally and are made ofresilient material so that a needle can be inserted from the outer faceof the plug 14 and held in place by inserting plug I2 to hold the ballin the spherical cavity.

The end of the tube or sleeve Il) away from the needle S has externalthreads i7, and a barrel 18 with internal threads is threaded over theend of the tube It). The barrel I8 has internal shoulders 19, and aspacer 20 and gasket 21 are clamped between these shoulders and the endof the tube I@ by turning the barrel 18 on the threads 17.

Within the tube 9 a plunger 22 moves toward and away from the end of theneedle 8 to draw in and expel liquid through the needle. The plungermakes a close t with the inner walls of the tube 9 and is formed ofmaterial such as polytetrailuoroethylene which will enable `it to slideeasily in the tube. The plunger 22 is threaded onto the end of a plungerrod 23 which extends through central openings in the spacer 2li andgasket 2l, through the barrel 18, and out beyond the end of the barrel.The outer end of the rod 23 is threaded, and the threaded portioncarries at its end a hand knob 24- whereby an operator can move theplunger in the tube 9.

A compression spring 25 surrounds the portion of the plunger rod 23which is inside the barrel 18. One end of the spring engages a snap ring26 fitted into a groove in the rod, and the other end of the springengages a partition 27 which divides the interior 0f the barrel I3 andhas a central opening through which the plunger rod 23 passes. Thelength of the spring 2S is such that the spring resiliently presses theplunger 22 against the end of theneedle. 8. As shown in FIGURE 1, if theplunger is moved away from the needle 3 to draw liquid into the syringe,the spring 2S is compressed.

To hold the plunger in a position away from the needle 8 against theforce ofthe spring, a stop 28 is threaded onto the plunger rod 23. Thestop has radially extending pins 29 which when the plunger and plungerrod move towards the needle 8 engage the end of the barrel 1S. Twodiametrically opposed slots 3d formed in the barrel 18 extend from theend of the barrel and parallel to the axis of the barrel. These slotshave a width slightly greater than the diameter of the pins 29 so thatwhen the plunger rod 23 is rotated within the barrel 18 to line the pins29 with the slots Sil, the plunger and plunger rod are released and thespring 25 moves them towards the end of the needle 8 within the tube toexpel liquid drawn into the tube when the plunger was moved in theopposite direction.

Preferably only a small degree of rotation is used to release theplunger rod and to insure this manner of operation recesses 3l areformed in the end of the barrel 18 on opposite sides of the slots 30(see FIGURE 2), and after the plunger has been pulled away from theneedle to draw liquid into the tube 10, the plungerrod isl allowed tomove back under the pressure of the spring 25, and,

areaal? at the same time, the-rod is turned so ythat the pins V2.9 As isalso` go'into recesses 31 as shown in FIGURE 3. shown in FIGURE 3, onlya small rotation of the plunger rod is required to move the pins 29 fromthe recesses Y31 intotheslotsStl.

The stop is turned on the plunger'rod23to 'position it onY theV rod andthereby determine the amount of fluidA which is ejected from the syringewhen the' plunger 22 moves forwardly against the needle 8. It is held inany desiredposition by a lock nut 32. To obtain the desiredl Infusingourlsyringe an operator lls the syringe intheV conventional manner. bydrawing more liquid or gas than is required into the tube 9 and allowsthe plunger to return .toward the needle until theV pins 29 move intothe recesses 31 and prevent further inward movement of the plunger. Theoperator then withdraws the needle from the sampleasupply andinsertsthe. needle 'in a serum cap which forms part of the .gaschromatographic;apparatus in which the sample is to be analyzed. HeVthen turns the plunger rod to alignthe pins 29 with the slots.' Thespring 25 then moves the plunger l22 inwardly against the This is thezero position'. T heV stop 23 is'then end ofthe needle to eject asamplehaving 'the desired volume. So longl as the positionVV of the stop28 on the plunger rod 24 is not disturbed, all samples willhaveprecisely the same Vvolume' and will have been injected into thechromatographic apparatus at the same rate.

FIGURES 5 to 7, inclusive, show a modified form of our syringe. Thismodified form is the same as the syringe shown in FIGURES 1 to 4,inclusive, except that the barrel 18er' vthe first embodimentr isreplaced by a barrel y40 33 which is internally threaded at both ends,one end being vthreadedto the tube 9 and the other end having threadedwithinit la Isecond barrel 34. This second barrel has a partition 35which has acentral opening throughfwhich the plunger rod 23 passeswandwhich engages one end of the spring 25. Thesecond barrel also has slots30 and recesses .31 which are ythe same as the correspondingly numberedslots 'and recesses in the embodiment shown yin FIGURES f1-to 4,inclusive. Y y Y,

The operation of the modied form of our hypodermic syringe is the sameas that described with reference to the embodiment shown in yFIGURES lto- 4, inclusive, except that instead of adjusting the stop 2.3 on theplungerV Vrod'i it away from thebarrel 33, aV shim is inserted, and thenthe barrel 34-is turned to bring it up against the shim 36. By usingshims of various thicknesseathe syringe can be adjusted to .producesamples of correspondingly various volumes. y U-shaped so that'fthey can*beY slipped around the threaded portion of the barrel 34 withoutremoving that barrel from the barrel 33. y

From .the foregoing, it is apparent that we have invented a hypode'rmicsyringe which can be used to obtain samples of uniform volume which areejected from the syringe at a uniform rate..V These results can beobtained without prior practice or training in the use of a syringe.

. While we have described certain presently preferred embodiments of ourinvention, it is to be understood that it may .be otherwisev embodiedwithin the scope of the appended claims.. i

We claim: Vl. A hypodermic syringe comprising, l A. a hollow glass tu'oeclosed at one end, B. a hypodermic needle mounted in the closed end ofthe tube,y C. a plunger movable within said tube toward and away fromsaid needle, Y I l Df a'metal sleeve surrounding the'glass tube, v

E. a first barrel secured tothe end of the sleeve away from the needle,,F. ya second barrel concentrically mounted ony the first barrel andmovable axially with respect' to thel first barrel toward and away vfromthe needle, Y `G'. a plunger rod carrying said plunger at one of itsends andextending into said tube, through both said bar- `rels, andbeyond the end of the second barrel, H. a compression spring surroundingthe plunger rod and connected to the rod to lresiliently press it andthe plunger toward the needle endV of the tube, L a handle'on theendofthe plunger rod which extends beyond the endfof the secondbarrel'whereby the plunger rod and plunger'may be withdrawn in said tubeaway from the needle and against the force of said spring, land l. meanson the second barrel forv releasably holding the plunger rodiin aposition withdrawn from the needle, axial movement of the second'barrelwith respect to the first barrel' determining the amount of Vmovement ofthe plunger rodand plunger toward the needle under the force of saidspring upon release ofy said plunger rod holding means. l 2.A Apparatusfor regulating and dispensing fluid samples in.predetermined"V amountsfrom a syringe having a cylinder, a hypodermic needle mountedin oneendof the 23 to obtain the desired volume ofsample, thebarrelrsi.

is yturned in the barrel 33 to move it axially with respect` to thebarrel33rand the tube 9. v,The amountthat the barrel 34 moves withrespect to thebarrel 33 determines the distance that the plunger 22moves in the'ktubel gato,

producethe required volume of sample. To operate this modified syringe,the barrel 34 is first'turne'd to move it f ltoward the tube 9 so thatthe plunger 22yrestsfagainstthe end of theneedle 8 in the tube 9.' Thestop 2S is then turned'to move it along the plunger rod 23 ,until thepins 29 just clear therrecesses 31 when the plungerr'od is turned-ffl tomove the pins into the recesses. l The barrel 34 fisth'en turned in theybarrelv33 to'rnove itaxially'awayjfrom the barrel 33' inthey distancethat .the plunger'ZZ "must 'move f to eject the required sample ofvolume.' x Theoperation of.l this modified syringe is the-n the'same asthatdescribed with-.reference to the first form ofour syringe,

ToY enable the operator toV adjusty thefsyringe to p oduce portionY ofthelbarrel 34;? Thebarrel 'is turned to-,mov

70: the samples having volumes vary-ing in amount as piickly'rgV easilyand.V accuratelyf'as possible,V we-'provideshirns '36, f1.- i one ofwhich'gis showningFlGURE 7; ',These vare placed betwcenthefbarrels `33yand iand 'around the thr-:aded` finder, Vsaid apparatus comprising,

' A. a first barrel' secured to the cylinderat the 'end of thecylinderremoved from the needle, 'l

' B. a second-barrel, mounted concentrically on atleast a portion of thefirst barrel and movable axially with i respect totheV rst barrel towardVand away yfrom the needle, Y

C. a plunger rod having oneendsecured to the plunger v and extending,throughV bothfsaid barrels and beyond theendof the second barrel; i v

AVD. a-,co'mpression spring `.within said barrels and surroundingsaidrod and connected .to the rod to resiliently press it1and theplunger toward the needle,

E. means on the end "ofthe rod' which extends from the, second barrel'for manually withdrawing the plungerand plunger rodjin s'aidcylinderaway from (i the needie and against theforce of said spring, and

F.,fmeanson the secondfharrel for releasably'holding needle; Y ,Y-G.v`axialfnr1ovement Vofthe `second barrel with respect to "".the'gfirst Vbarrel?determining vthe distance that 'the As Vappears in FIGURE7, the shims are 'Y ,the-'plunger rod in a position withdrawn Vfrom the.

fr-plunger.movesiin the fcylinderawayfrom he Veedle when the plunger rodis withdrawn to a position in which it is held by said plunger rodholding means. 3. A hypodermic syringe comprising, v A. a hollow glasstube closed at one end, B. a hypodermic needle mounted in the closed endof the tube, C. a plunger movable within said tube toward and away fromsaid needle, D. a plunger rod movable within said tube and on one end ofwhich the plunger is mounted, E. a metal sleeve surrounding the glasstube, F. a barrel threaded on the end of the sleeve away from theneedle, G. said plunger rod extending through said barrel and beyond theend of the barrel away from said sleeve, H. a compression spring (1)surrounding the plunger rod Within the barrel, (2) one end of the springengaging the plunger rod and resiliently urging the plunger rod andplunger toward the needle-end of the tube, I. a stop on the plunger rodextending radially from the rod to engage the end of the barrel as therod moves toward the needle, and

J. a slot extending inwardly from the end of the barrel and parallel tothe axis of the barrel in which the stop can be placed by rotating theplunger rod to permit further movement of the plunger and plunger rodunder pressure of the spring,

K. said stop being adjustable along the length of the rod whereby theamount of movement of the plunger and plunger rod upon release of thestop can be adjusted.

References Cited in the le of this patent UNITED STATES PATENTS 405,100Kloppe June 11, 1889 727,069 Bomeisler May 5, 1903 2,792,157 Gilman May14, 1957 2,798,647 Broadwin July 9, 1957 3,075,674 Hruskoci Jan. 29,1963 3,094,155 Taramasso et al June 18, 1963

1. A HYPODERMIC SYRINGE COMPRISING, A. A HOLLOW GLASS TUBE CLOSED AT ONEEND, B. A HYPODERMIC NEEDLE MOUNTED IN THE CLOSED END OF THE TUBE, C. APLUNGER MOVABLE WITHIN SAID TUBE TOWARD AND AWAY FROM SAID NEEDLE, D. AMETAL SLEEVE SURROUNDING THE GLASS TUBE, E. A FIRST BARREL SECURED TOTHE END OF THE SLEEVE AWAY FROM THE NEEDLE, F. A SECOND BARRELCONCENTRICALLY MOUNTED ON THE FIRST BARREL AND MOVABLE AXIALLY WITHRESPECT TO THE FIRST BARREL TOWARD AND AWAY FROM THE NEEDLE, G. APLUNGER ROD CARRYING SAID PLUNGER AT ONE OF ITS ENDS AND EXTENDING INTOSAID TUBE, THROUGH BOTH SAID BARRELS, AND BEYOND THE END OF THE SECONDBARREL, H. A COMPRESSION SPRING SURROUNDING THE PLUNGER ROD ANDCONNECTED TO THE ROD TO RESILIENTLY PRESS IT AND THE PLUNGER TOWARD THENEEDLE END OF THE TUBE, I. A HANDLE ON THE END OF THE PLUNGER ROD WHICHEXTENDS BEYOND THE END OF THE SECOND BARREL WHEREBY THE PLUNGER ROD ANDPLUNGER MAY BE WITHDRAWN IN SAID TUBE AWAY FROM THE NEEDLE AND AGAINSTTHE FORCE OF SAID SPRING, AND J. MEANS ON THE SECOND BARREL FORRELEASABLY HOLDING THE PLUNGER ROD IN A POSITION WITHDRAWN FROM THENEEDLE, K. AXIAL MOVEMENT OF THE SECOND BARREL WITH RESPECT TO THE FIRSTBARREL DETERMINING THE AMOUNT OF MOVEMENT OF THE PLUNGER ROD AND PLUNGERTOWARD THE NEEDLE UNDER THE FORCE OF SAID SPRING UPON RELEASE OF SAIDPLUNGER ROD HOLDING MEANS.